About 1000 alien species have been reported in the Mediterranean Sea, much more than other European seas. A small number of marine invasive alien species impact human health negatively, being venomous and poisonous. Recently, news of the death of three Libyan fishers who consumed poisonous silver-cheeked toadfish, have drawn the attention of media and public. As marine scientists, engaged in the study of alien species, we wish to provide accurate information concerning these new health hazards.
Among the alien species recorded in the Mediterranean Sea, ten are noted as human health hazards – seven fish, a sea urchin, a scyphozoan jellyfish and a hydrozoan. Most have either been post-millennial records or have greatly increased their spread in the last decade. All originate in the Indian Ocean or the Indo-west Pacific Ocean and are considered to have entered the Mediterranean through the Suez Canal. Four species are confined to the Levant and Tunisia, and the rest are recorded further west and north (e.g. Silver-cheeked toadfish Lagocephalus sceleratus, Dusky spinefoot Siganus luridus, Marbled spinefoot Siganus rivulatus, Nomadic jellyfish Rhopilema nomadica and Lionfish Pterois miles), the largest populations occur in the Levant. With rising temperatures, it is likely these thermophilic species will expand their range.